Supermoon Lunar Eclipse September 27-28, 2015

Starting on the night of September 27th, 2015, a supermoon lunar eclipse will occur. This gallery page contains visualizations about this specific event as well as other multimedia items about supermoons, eclipses, and NASA's Lunar Reconnaissance Orbiter (LRO). This page will update weekly - so continue to check here for new items.

On the night of September 27th, 2015, a supermoon lunar ecllipse will be viewable in the night sky for those living in North and South America. Those living in Europe and Africa can view it in the early morning hours of September 28th.
This video explains what a supermoon lunar eclipse is, and how rare it has been over the last century.

On September 28, 2015 (the night of the 27th in many places), the Moon will be full at the same time that it is closest to Earth for the year, a coincidence sometimes called a supermoon. As it happens, this largest Full Moon occurs within the Earth's shadow, creating the added spectacle of a total lunar eclipse.
The Moon's orbit is very slightly elliptical and therefore somewhat off-center relative to the Earth. Each month, the Moon passes through points in its orbit called perigee and apogee, the closest and farthest points from the Earth for that month. Some perigees are a little closer than others. The closest perigee for 2015 occurs on September 28 at around 1:52 Universal Time, when the Moon will be 356,877 kilometers (221,753 miles) away. This is only an hour before the time of peak full Moon at 2:51 UT, when the Moon's ecliptic longitude differs from the Sun's by exactly 180 degrees.
All of this takes place during a total lunar eclipse. The Moon makes first contact with the umbra, the central part of the Earth's shadow, at 1:07 UT, and it doesn't completely emerge until 4:27 UT.
If we define a supermoon as a Full Moon that coincides with the closest perigee in a given year, then supermoons occur every 14 months, with occasional skips. The anomalistic month — the time between two perigees — is two days shorter than the cycle of phases, called the synodic month; the perigees "lap" the phases after 14 months.
Total lunar eclipses involve a third cycle, the draconic month. The Moon's tilted orbit crosses the Earth-Sun plane at one of two points called nodes; a draconic month is the time it takes the Moon to return to the same node. Total lunar eclipses happen when a node crossing coincides with a Full Moon. Only then does the Moon's orbit carry it close enough to the Earth-Sun line to actually pass through the shadow cast by the Earth.
A supermoon eclipse requires the alignment of all three cycles, the synodic, anomalistic, and draconic months, and this happens every 18 years 11 days, a period known as a saros. Eclipses separated by this period tend to share certain properties and are grouped into families, or saros series. The 2015 supermoon eclipse is the first in Saros 137. There will be seven more supermoon eclipses in this series, the last in December of 2141.
The animation begins at the end of August showing that perigee and Full Moon miss each other by about a day. It then shows apogee on September 14, when the Moon is almost 32 Earth diameters away. It ends on September 28, the day of the supermoon eclipse, when the distance to the Moon is 28 Earth diameters. The Moon graphic in the upper left shows the change in the Moon's apparent size as it moves closer and farther in its orbit, as well as its copper color during the eclipse.
The relative sizes of the Earth and Moon in the main orbit graphic are exaggerated by a factor of 15 to make them more easily visible.

On the evening of September 27, 2015 in the Americas (early morning on September 28 in Europe and most of Africa), the Moon enters the Earth’s shadow, creating a total lunar eclipse, the last of four visible in the Western Hemisphere in a span of 18 months. This animation shows the changing appearance of the Moon as it travels into and out of the Earth’s shadow, along with the times at various stages. Versions of the animation have been created for each of the four time zones of the contiguous United States, as well as one for Universal Time.
All of South America and most of North and Central America will see the entire eclipse, while those west of roughly 120°W will see it in progress at moonrise. You won’t need special equipment to see it. Just go outside and look up!
The penumbra is the part of the Earth’s shadow where the Sun is only partially covered by the Earth. The umbra is where the Sun is completely hidden. The Moon's appearance isn't affected much by the penumbra. The real action begins when the Moon starts to disappear as it enters the umbra at about 9:07 Eastern Daylight Time. An hour later, entirely within the umbra, the Moon is a ghostly copper color, and this lasts for over an hour before the Moon begins to emerge from the central shadow.
The view in these animations is geocentric. Because of parallax, the Moon's position against the background stars will look a bit different for observers at different locations on the surface of the Earth. The Moon is in the southwestern part of the constellation Pisces.

Typically, the Lunar Reconnaissance Orbiter (LRO) spacecraft flies over the night side of the Moon every two hours, spending about 45 minutes in darkness. Because LRO is powered by sunlight, it uses a rechargeable battery to operate while on the night side of the Moon and then charges the battery when it comes back around into daylight.
During the total lunar eclipse of September 27-28, 2015, however, LRO emerges from the night side of the Moon only to find the Sun blocked by the Earth. LRO needs to travel an entire orbit before seeing the Sun again, relying continuously on its battery for almost three hours.
LRO won’t be in any real danger as long as its power consumption is handled carefully. Except for LRO's infrared radiometer, called Diviner, its scientific instruments will be turned off temporarily, while vital subsystems like the heaters will remain on. LRO will be closely monitored throughout the eclipse.
Diviner maps the temperature on the Moon's surface along a swath below LRO's orbit. During the eclipse, the instrument will precisely measure the rapid temperature changes that occur as the Moon enters and leaves the Earth's shadow. When compared with normal daylight variations, these measurements will reveal new details about the top centimeter (half-inch) of lunar regolith. Diviner wasn't specifically designed for this experiment, but as scientists have gained experience with the LRO spacecraft, they've thought of new and creative ways of using its instruments.
This animation shows the Moon as it might look through a telescope on Earth, along with LRO’s orbit, its view of the Sun, and a fuel gauge showing received sunlight and the battery’s charge.

On September 28, 2015 Universal Time (the evening of the 27th for the Americas), the Moon enters the Earth’s shadow, creating a total lunar eclipse. When viewed from the Moon, as in this animation, the Earth hides the Sun. A red ring, the sum of all Earth’s sunrises and sunsets, lines the Earth’s limb and casts a ruddy light on the lunar landscape. With the darkness of the eclipse, the stars come out.
The city lights of North and South America and of western Europe and Africa are visible on the night side of the Earth. The part of the Earth visible in this animation is the part where the lunar eclipse can be seen.

Dial-A-Moon

Month: Day: UT Hour:

New: Click on the image to download a high-resolution version with labels for craters near the terminator.

The animation archived on this page shows the geocentric phase, libration, position angle of the axis, and apparent diameter of the Moon throughout the year 2015, at hourly intervals. Until the end of 2015, the initial Dial-A-Moon image will be the frame from this animation for the current hour.

Lunar Reconnaissance Orbiter (LRO) has been in orbit around the Moon since the summer of 2009. Its laser altimeter (LOLA) and camera (LROC) are recording the rugged, airless lunar terrain in exceptional detail, making it possible to visualize the Moon with unprecedented fidelity. This is especially evident in the long shadows cast near the terminator, or day-night line. The pummeled, craggy landscape thrown into high relief at the terminator would be impossible to recreate in the computer without global terrain maps like those from LRO.

The Moon always keeps the same face to us, but not exactly the same face. Because of the tilt and shape of its orbit, we see the Moon from slightly different angles over the course of a month. When a month is compressed into 24 seconds, as it is in this animation, our changing view of the Moon makes it look like it's wobbling. This wobble is called libration.

The word comes from the Latin for "balance scale" (as does the name of the zodiac constellation Libra) and refers to the way such a scale tips up and down on alternating sides. The sub-Earth point gives the amount of libration in longitude and latitude. The sub-Earth point is also the apparent center of the Moon's disk and the location on the Moon where the Earth is directly overhead.

The Moon is subject to other motions as well. It appears to roll back and forth around the sub-Earth point. The roll angle is given by the position angle of the axis, which is the angle of the Moon's north pole relative to celestial north. The Moon also approaches and recedes from us, appearing to grow and shrink. The two extremes, called perigee (near) and apogee (far), differ by more than 10%.

The most noticed monthly variation in the Moon's appearance is the cycle of phases, caused by the changing angle of the Sun as the Moon orbits the Earth. The cycle begins with the waxing (growing) crescent Moon visible in the west just after sunset. By first quarter, the Moon is high in the sky at sunset and sets around midnight. The full Moon rises at sunset and is high in the sky at midnight. The third quarter Moon is often surprisingly conspicuous in the daylit western sky long after sunrise.

Celestial north is up in these images, corresponding to the view from the northern hemisphere. The descriptions of the print resolution stills also assume a northern hemisphere orientation. (There is also a south-up version of this page.)

From this birdseye view, it's somewhat easier to see that the phases of the Moon are an effect of the changing angles of the sun, Moon and Earth. The Moon is full when its orbit places it in the middle of the night side of the Earth. First and Third Quarter Moon occur when the Moon is along the day-night line on the Earth.

The First Point of Aries is at the 3 o'clock position in the image. The sun is in this direction at the spring equinox. You can check this by freezing the animation at the 1:03 mark, or by freezing the full animation with the time stamp near March 20 at 23:00 UTC. This direction serves as the zero point for both ecliptic longitude and right ascension.

The north pole of the Earth is tilted 23.5 degrees toward the 12 o'clock position at the top of the image. The tilt of the Earth is important for understanding why the north pole of the Moon seems to swing back and forth. In the full animation, watch both the orbit and the "gyroscope" Moon in the lower left. The widest swings happen when the Moon is at the 3 o'clock and 9 o'clock positions. When the Moon is at the 3 o'clock position, the ground we're standing on is tilted to the left when we look at the Moon. At the 9 o'clock position, it's tilted to the right. The tilt itself doesn't change. We're just turned around, looking in the opposite direction.

The subsolar and sub-Earth points are the locations on the Moon's surface where the sun or the Earth are directly overhead, at the zenith. A line pointing straight up at one of these points will be pointing toward the sun or the Earth. The sub-Earth point is also the apparent center of the Moon's disk as observed from the Earth.

In the animation, the blue dot is the sub-Earth point, and the yellow dot is the subsolar point. The lunar latitude and longitude of the sub-Earth point is a measure of the Moon's libration. For example, when the blue dot moves to the left of the meridian (the line at 0 degrees longitude), an extra bit of the Moon's western limb is rotating into view, and when it moves above the equator, a bit of the far side beyond the north pole becomes visible.

At any given time, half of the Moon is in sunlight, and the subsolar point is in the center of the lit half. Full Moon occurs when the subsolar point is near the center of the Moon's disk. When the subsolar point is somewhere on the far side of the Moon, observers on Earth see a crescent phase.

The Moon's orbit around the Earth isn't a perfect circle. The orbit is slightly elliptical, and because of that, the Moon's distance from the Earth varies between 28 and 32 Earth diameters, or about 356,400 and 406,700 kilometers. In each orbit, the smallest distance is called perigee, from Greek words meaning "near earth," while the greatest distance is called apogee. The Moon looks largest at perigee because that's when it's closest to us.

The animation follows the imaginary line connecting the Earth and the Moon as it sweeps around the Moon's orbit. From this vantage point, it's easy to see the variation in the Moon's distance. Both the distance and the sizes of the Earth and Moon are to scale in this view. In the full-resolution frames, the Earth is 50 pixels wide, the Moon is 14 pixels wide, and the distance between them is about 1500 pixels, on average.

Note too that the Earth appears to go through phases just like the Moon does. For someone standing on the surface of the Moon, the sun and the stars rise and set, but the Earth doesn't move in the sky. It goes through a monthly sequence of phases as the sun angle changes. The phases are the opposite of the Moon's. During New Moon here, the Earth is full as viewed from the Moon.

The animations on this page illustrate the Moon’s orbit and its role in lunar and solar eclipses. A solar eclipse happens when the Moon’s shadow falls on the Earth, while a lunar eclipse happens when the Earth’s shadow falls on the Moon.
Eclipses can only happen at New and Full Moon, when the Earth, Moon, and Sun are all in a straight line. But they don’t happen every New and Full Moon, because the Moon’s orbit is tilted by about 5 degrees. As the Earth and Moon travel around the Sun, the tilt of the Moon’s orbit changes direction relative to the Sun.
This is analogous to the way the tilt of the Earth causes seasons. Just like winter and summer happen every six months, eclipses tend to occur on a roughly six-month cycle.
Unlike most eclipse shadow diagrams, the first three animations here don’t greatly exaggerate the scale of the Earth and Moon. They are only 2x their true scale. The view is exactly perpendicular to the Earth-Sun line. The angle of the Moon’s orbital tilt and the “tapering” of the shadows are both accurate. The orbit happens to be calculated for the months preceding the April 15, 2014 total lunar eclipse.

On August 10, 2014, the Moon will be full at the same time that it is closest to Earth for the year. This coincidence is sometimes called a supermoon.
The Moon's orbit is very slightly elliptical and therefore somewhat off-center relative to the Earth. Each month, the Moon passes through points in its orbit called perigee and apogee, the closest and farthest points from the Earth for that month. Some perigees are a little closer than others. The closest perigee for 2014 occurs on August 10 at around 17:49 Universal Time, when the Moon will be 356,896 kilometers (221,765 miles) away. As it happens, this is only a few minutes before the time of peak full Moon at 18:10 UT, when the Moon's ecliptic longitude differs from the Sun's by exactly 180 degrees.
How often does this happen? The period between perigees, called the anomalistic month, is 27.55 days, on average, while the time between Full Moons, called the synodic month, is 29.53 days. These two periods sync up every 413 days, or 1.13 years. 15 anomalistic months are about as long as 14 synodic months, so that's how often the pattern repeats.
Recently, a much broader definition of "supermoon" has taken hold. It includes both Full and New Moons, and perigee merely needs to be "close enough," generally within a couple of days. By this definition, there are six or seven supermoons every year, half of which can't be observed. Not so super!
The actual shape of the Moon's orbit is another source of confusion. The orbit is often depicted as an almost cigar-shaped ellipse, but this is a misleading exaggeration. If you were to draw the orbit on a sheet of paper, its deviation from a perfect circle would be less than the thickness of your pencil point. The 50,000 kilometer (30,000 mile) difference between perigee and apogee is almost entirely due to the orbit being off-center. The difference between the semimajor and semiminor axes is less than 1000 kilometers (600 miles).
The animation begins in mid-July, showing that perigee and Full Moon miss each other by about a day. It then shows apogee on July 28, when the Moon is almost 32 Earth diameters away. It ends on August 10, the day of the supermoon, when the distance to the Moon is 28 Earth diameters. The Moon graphic in the upper left shows the change in the Moon's apparent size as it moves closer and farther in its orbit. (The relative sizes of the Earth and Moon in the main orbit graphic are exaggerated by a factor of 15 to make them more easily visible.)

On the night of September 27th, 2015, a supermoon lunar ecllipse will be viewable in the night sky for those living in North and South America. Those living in Europe and Africa can view it in the early morning hours of September 28th.
This video explains what a supermoon lunar eclipse is, and how rare it has been over the last century.

What can cause the full Moon to quickly darken, then glow red? A lunar eclipse: a striking display of orbital mechanics that occurs when the Moon passes through the Earth's shadow. To learn more, watch the video below.

When the moon passes through the Earth's shadow, it causes the moon to look very unusual for a short period of time. This event is called a lunar eclipse, and it occurs roughly twice a year. Learn more about how lunar eclipses work in this video!

These videos and animations are available in both standard formats as well as stereoscopic 3D for those who can view it. We've included left and right eye clips, a side-by-side version, and an anaglyph (red/blue) version of the narrated video, and left and right eye clips for each of the animations. The labels next to each link will help you pick!

A number of people who've seen the annual lunar phase and libration videos have asked what the other side of the Moon looks like, the side that can't be seen from the Earth. This video answers that question. (Update: The video was selected for the SIGGRAPH 2015 Computer Animation Festival.)
Just like the near side, the far side goes through a complete cycle of phases. But the terrain of the far side is quite different. It lacks the large dark spots, called maria, that make up the familiar Man in the Moon on the near side. Instead, craters of all sizes crowd together over the entire far side. The far side is also home to one of the largest and oldest impact features in the solar system, the South Pole-Aitken basin, visible here as a slightly darker bruise covering the bottom third of the disk.
The far side was first seen in a handful of grainy images returned by the Soviet Luna 3 probe, which swung around the Moon in October, 1959. Lunar Reconnaissance Orbiter was launched fifty years later, and since then it has returned hundreds of terabytes of data, allowing LRO scientists to create extremely detailed and accurate maps of the far side. Those maps were used to create the imagery seen here.
In the first of the two viewpoints, the virtual camera is positioned along the Earth-Moon line at a distance of 30 Earth diameters from the Moon and 60 ED from the Earth. The focal length is equivalent to a 2000 mm telephoto lens on a 35 mm SLR, making the horizontal field of view about one degree. The view is consistent with what you might see through an amateur telescope at these distances.
In the second view, the virtual camera is much closer to the Moon, only 1.2 ED, versus 31 ED from Earth. The camera focal length has been reduced to 80 mm, giving a 25° horizontal field. The result is an Earth that appears much smaller, more closely resembling the way it would look to the eye from the surface of the Moon.

On April 15th, 2014 there will be a total lunar eclipse visible from North America. Noah Petro, LRO Deputy Project Scientist, discusses this unique event and what effect it will have on the Lunar Reconnaissance Orbiter (LRO).

Lunar Reconnaissance Orbiter Deputy Project Scientist Noah Petro discusses the Sept. 27th supermoon eclipse and some of the cool things that scientists have learned about our moon.
NASA will provide a LIVE FEED of Sunday's Supermoon eclipse. Click for details.